Health
Is myxomatous mitral valve disease common in Chow Chows?
No. It is predominantly a small-breed disease. A 45 to 70 pound Chow is well outside the population where it concentrates, and no cardiac condition is documented for the breed.
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Myxomatous Mitral Valve Disease (MMVD) in Chow Chows
Quick answer
Is myxomatous mitral valve disease common in Chow Chows?
No. It is predominantly a small-breed disease. A 45 to 70 pound Chow is well outside the population where it concentrates, and no cardiac condition is documented for the breed.
It is also, overwhelmingly, a small dog's disease. A Chow Chow is roughly four times the weight of a typical patient, which changes what a murmur in this breed most likely means.
Owners of older Chows who have been told the murmur is loudest over the left apex, and anyone who has read that MMVD is the most common disease in their breed and wants to know whether that is true here.
Important reminder
This guide is not medical advice. If your dog shows pain, sudden behavior change, or worsening symptoms, consult a licensed veterinarian.
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What this problem looks like
Myxomatous mitral valve disease is a progressive degeneration of the valve between the left atrium and left ventricle, allowing blood to leak backwards with every beat. It produces a murmur long before it produces symptoms, and only a proportion of affected dogs ever reach congestive heart failure. In the Chow Chow it is a plausible finding in old age rather than a breed expectation.
Common triggers
- Advancing age, with valve degeneration accumulating over years
- An incidental murmur discovered at a routine or pre-anesthetic examination
- High blood pressure increasing the workload across the valve
- Untreated thyroid disease altering heart rate and contractility
- Sudden rupture of a valve chord, which converts stable disease into an emergency
Across dogs as a whole it is the single most common acquired heart disease, but its distribution is heavily skewed toward small breeds. For the Chow Chow, with an adult weight of 45 to 70 pounds and no cardiac condition among its ten documented health issues, it should be treated as one of several explanations for a murmur rather than the assumed one.
Why this happens
Breed factors
The honest breed answer is that the Chow's construction neither causes nor protects against valve degeneration, and that the disease's strong small-breed clustering makes it less likely here than the breed pages suggest. Where Chow biology genuinely matters is in detection and tolerance. A grooming rating of 5 out of 5 describes a coat dense enough to mute the murmur and hide chest effort. An energy rating of 2 and exercise need of 2 remove the reduced-stamina signal that reveals early failure in active dogs. Heat intolerance means that any loss of cardiac reserve shows up first as summer collapse rather than as exercise limitation.
Environment factors
The environment does not degrade a valve, but it determines when the consequences appear. Warm, humid conditions demand extra cardiac output for cooling, so a Chow with a compensated leak is most likely to declare itself on a hot afternoon. Salty food raises circulating volume. Long gaps between veterinary examinations delay the murmur's discovery, and in a breed nobody thinks of as cardiac, those gaps tend to be longer than average.
What you can do at home (once it is not an emergency)
When to talk to your vet
Go immediately for breathing with effort while at rest, an open mouth in a dog lying still, a refusal to settle or lie down at night, coughing that brings up frothy or pink fluid, collapse, or a sleeping breath rate above forty. Those signs indicate fluid in the lungs and are treated as an emergency. Do not attempt to judge by gum colour, because a Chow's blue-black oral pigment makes that check unreliable, and say so to any unfamiliar emergency team. Book a normal appointment within a week or two for a new cough that appears when the dog lies down, a breath count that has drifted above thirty-five, reduced appetite over several days, or a belly that has begun to look fuller.
At home, alongside your vet's plan
- Count sleeping breaths for thirty seconds once a week, double the number, and record it with the date, because a trend is what matters rather than any single figure.
- Ask for the murmur grade and the location where it was loudest to be written into the record at every visit, so change over years is measurable.
- Weigh monthly, since fluid retention can look like gradual weight gain under a coat this thick.
- Remove salty human food from the household entirely, including cheese, deli meats and anything cooked with stock.
- Keep all activity gentle, flat and self-paced, and confine walks to cool hours so that cooling never competes with a compromised circulation.
- Record thirty seconds of video if your dog ever coughs, wobbles or breathes oddly, because none of it will happen in the consulting room.
More Chow Chow health & behavior issues
- Chow Chow ARVC: Fainting, Rhythm Disorders & What It Really Is
- Chow Chow Heart Disease: Is DCM Really a Risk for This Breed?
- Chow Chow Liver Shunts: What Owners Actually Pay
- Chow Chow Pancreatitis and Diabetes: One Organ, Two Failures
- Chow Chow Pancreatitis: The Praying Position and the Holiday Trigger
- Chow Chow Allergic Reactions: Warning Signs & Emergency Steps
- Chow Chow Genetic Obesity Risk: When Hunger Itself Is the Problem
- Chow Chow Hip Dysplasia Prevalence: What Screening Numbers Mean
- Chow Chow Immune-Mediated Thyroiditis: The Stage Before Symptoms
- Chow Chow Luxating Patellas: The Skip Step and What Grades Mean
- Chow Chow Obesity: You Cannot See It Under That Coat
- Chow Chow Patellar Luxation Surgery: Deciding and Recovering
- Chow Chow Separation Anxiety: Or Is It Boredom, Heat or Territory?
- Chow Chow Skin Allergies: Finding the Itch Under the Coat
- Chow Chow Skin Infections: What the Mane Traps Against the Skin
Myxomatous Mitral Valve Disease Mmvd in other breeds
- Jack Russell Terrier Myxomatous Mitral Valve Disease: Signs
- Labradoodle Mmvd: Signs, Causes & What to Do
- Maltese Mmvd: Signs, Causes & What to Do
- Miniature Schnauzer Myxomatous Mitral Valve Disease: Signs
- Poodle Mmvd: Signs, Causes & What to Do
- Rottweiler Mmvd: Signs, Causes & What to Do
- Schnauzer Standard Myxomatous Mitral Valve Disease: Signs
- Yorkshire Terrier Myxomatous Mitral Valve Disease: Signs
- Bernese Mountain Dog Mitral Valve Disease: Stages Explained
- Chinese Shar-Pei MMVD: The Breed's Most Common Heart Issue
See all Chow Chow health problems, which breeds are prone to myxomatous mitral valve disease mmvd, or the full Chow Chow breed guide for temperament, exercise needs and ownership costs.
What to expect, and how you know it is working
A murmur discovered in a symptom-free dog usually leads to imaging and then a recheck in six to twelve months. Progression to heart enlargement, where it happens, is measured in years rather than months in most dogs. Once medication starts, expect a recheck within two weeks and then every three to six months.
Success is a stable sleeping breath count, a dog who eats, sleeps and takes his short walk normally, and heart size that has not changed between imaging appointments. The murmur remains, because valve degeneration is not reversible.
How a leaking valve becomes a sick dog
The valve does not fail all at once. Early on, the leak is small and the heart compensates without any visible consequence, which is why so many dogs live for years with a murmur and no symptoms at all. Over time the volume flowing backwards increases, the left atrium stretches to accommodate it, and pressure rises in the vessels draining the lungs. Eventually fluid is pushed out of those vessels into lung tissue, and that is congestive heart failure.
The important consequence for owners is that the murmur and the failure are separated by a long interval, often years. The clinical question is never simply whether a murmur exists but where the dog sits on that progression, and the tools for answering it are chest radiographs, echocardiography and, at home, the sleeping respiratory rate.
A second complication is specific to a stretched left atrium. In some dogs a chord supporting the valve ruptures, or the atrium itself tears, and the deterioration that took years arrives in an evening. That is the reason a dog with known valve disease who suddenly becomes breathless at rest is an emergency rather than a reason to bring forward next month's appointment.
The breeds this disease belongs to
A murmur in an older Chow is worth investigating properly. Assuming in advance that it must be mitral valve disease, because a generic breed page said so, narrows the search prematurely.
- Cavalier King Charles Spaniels, in which the disease appears unusually early and is the subject of dedicated breeding schemes.
- Dachshunds, Miniature Poodles, Miniature Schnauzers, Chihuahuas and small terriers, where it is the leading cardiac diagnosis in old age.
- Small breeds generally, with the clear pattern that risk rises as adult body weight falls.
- Older dogs of any size, since valve degeneration is fundamentally age-related and larger dogs can develop it later and more slowly.
- The Chow Chow, only as a member of that last group. Cardiac disease is not on the breed's documented health list, and the breed's 45 to 70 pound adult weight sits well outside the small-dog population where MMVD concentrates.
The disease he did not have: Kenji's second opinion
Kenji was eleven and had a grade III murmur loudest over the left apex. His owner Rob found a breed health page listing myxomatous mitral valve disease as the most common condition in Chow Chows and arrived at the referral appointment already certain of the diagnosis. The echocardiogram found mild mitral thickening, but it also found something Rob had not expected: a substantially thickened left ventricle consistent with long-standing high blood pressure, which measured well above normal that day. Kenji's kidney values were mildly abnormal too, and the two findings were related. He was treated for hypertension and monitored, and the murmur was left alone. Rob still counts breaths every Sunday. What changed was that the treatment addressed what was actually driving the heart change rather than the label he had brought with him.
Key takeaway: A left apical murmur in an older dog has several possible causes. Getting the echo before accepting a breed-page diagnosis is what found the treatable one here.
Frequently asked questions
Is MMVD the most common disease in Chow Chows?
No. That claim is copied from small-breed data. The Chow Chow's documented health issues are hip dysplasia, elbow dysplasia, entropion, distichiasis, thyroid disease, cataracts, glaucoma, bloat, diabetes and stomach cancer, and no cardiac condition appears among them.
My older Chow has a left-sided murmur. What could it be?
Age-related valve degeneration is possible, and so are consequences of thyroid disease or high blood pressure, anaemia, and less commonly a cardiomyopathy. An echocardiogram is what distinguishes them, and it is worth doing rather than assuming.
How fast does valve disease progress?
Extremely variably. Many dogs carry a stable murmur for years without ever developing failure, while others progress over months. That variability is the main argument for tracking the sleeping respiratory rate at home rather than waiting for the next annual visit.
What is the sleeping respiratory rate and why does it matter?
It is the number of chest rises per minute while a dog is genuinely asleep, counted for thirty seconds and doubled. A settled dog should stay comfortably under thirty. A rising trend is the earliest and most reliable home indicator that fluid is beginning to accumulate.
Does treatment start as soon as a murmur is found?
No. Treatment decisions depend on whether the heart has begun to enlarge, which requires imaging. Medicating a dog with a murmur and a normal-sized heart is not standard practice, and this is why the echo is worth the money rather than an optional extra.
Does the Chow's coat make monitoring harder?
Yes, in two ways. Dense undercoat muffles the murmur unless the coat is parted, and it conceals both the chest effort and the weight change that would otherwise be visible. Home monitoring on this breed has to be numerical rather than observational.
Quick answers
View more answersHealth
What should I track if my Chow has a murmur?
Sleeping respiratory rate weekly and body weight monthly. A breath count trending above thirty in a settled dog warrants a call.
Health
When does a murmur become an emergency?
When the dog breathes with effort at rest, will not settle, coughs frothy fluid, or collapses. Go the same hour, and do not judge by gum colour in this breed.
Costs
Does a murmur mean medication straight away?
Usually not. Treatment normally begins once imaging shows the heart has started to enlarge, which is why an echocardiogram is worth doing before medicating.
Related DogBreedCompass guides
- Chow Chow heart murmurs explained – Murmur grading is the finding that starts this whole conversation.
- Chow Chow heart disease workup – The full cardiac diagnostic ladder is covered separately.
- Chow Chow thyroid disease – Thyroid disease is documented and alters cardiac findings.
- Chow Chow heat sensitivity – Heat load demands cardiac output this breed can least afford.
- Chow Chow cost breakdown – Echocardiography and lifelong medication reshape the annual budget.
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